1. Field of the Invention
The present invention relates to a digital communication system, and is more particularly related to protection of Digital Video Recording (DVR) content.
2. Discussion of the Background
Direct television broadcasting systems provide the consumers with high quality video and audio signals. Set-top based Digital Video Recording (DVR) to a hard disk is emerging as a needed feature in the highly competitive consumer electronics industry. With advances in digital recording and storage technologies, there is concern over unauthorized copying of the broadcast content.
The technology exists today to allow consumers to make a perfect and permanent personal digital copy of their favorite movie, for example. This capability to create high quality reproductions is recognized by the industry and consumers alike as a distinguishing product feature. However, because perfect digital copies can be readily made, content providers may be reluctant to supply programming to set-top boxes that incorporate unrestricted digital video recording. Thus, a potential near term impediment to the success of such a set-top box is the lack of an established mechanism to cost effectively prevent unauthorized reproduction of programming content. That is, content providers could be reluctant to support a set-top box that may lead to potential abuse of their material by the general consumers.
A number of scenarios exist whereby the consumer can distribute and replay the programming content of the set-top box. One approach would be as follows. A consumer records on a DVR enabled set-top certain content that is to be shared. Next, the consumer removes the hard drive from the set-top and installs the hard drive as a secondary drive in a PC. Thereafter, the consumer extracts content from the hard drive and posts the content on a web site in a format that is suitable for sharing.
Correspondingly, a consumer may find programming of interest on a web site. To view the content, the user installs a second hard drive in a PC. That is, the new second hard drive is in addition to the drive that is used to boot the PC and will be used for storing the digital content. Next, the user acquires and installs on the PC special software to format the new hard drive so that it is compatible with the set-top box. The user then captures the desired content to some PC storage (that is not the newly created set-top compatible disk), for example, downloading from the Internet. Special conversion software is then excuted to convert the digital video distribution image into a format compatible with the set-top box. Thereafter, the converted image is written to the new hard drive. The new hard drive is then removed from the PC and installed in the set-top box.
In addition to digital set-tops, a common DVD player may be used to share pirated content. Recordable DVD media and DVD recording devices will become sufficiently economical that the average consumer can obtain them for copying of programming content. If the source of the pirated content were a digital set-top, a conversion utility would be required to convert the digital formatted data that are stored on the set-top hard drive to that of the DVDs. The audio analogy of such a utility is a CD “ripper”, which permits a user to extract music tracks from a CD for storage on the computer or MP3 player. Given suitable source material and appropriate “video ripper” software, it is reasonable to assume that the DVD-R may become an important method of distributing pirated digital video.
Another obvious playback platform is the PC. Any PC with a broadband Internet connection is well positioned to acquire the digital video content. Assuming the PC in question has a DVD player and a DVD-R writer, it would be straightforward for the user to acquire or copy a digital movie and write it to a DVD-R. The owner of such a PC could, with relative ease, build a substantial library of DVD-R digital video movies. Pirate DVDs borrowed from friends could easily be copied and the broadband Internet connection would offer access to a wealth of digital video. It is reasonable to assume that pirates first, then legitimate companies will emerge to provide web portals for downloading digital video.
Understandably, content providers are apprehensive about the ability to maintain control of their product to avoid theft or misuse, which undercut profitability. If the content providers become too uneasy about possible compromise of their product, they may withhold programming and be disinclined from developing additional programming. Hence, any DVR product or mechanism that is endorsed, for example, by a subscription movie service (e.g., DIRECTV©) must provide reasonable assurances to the content providers that the content will not be used in a fashion that is objectionable.
Therefore, it is clear that some form of security is needed to protect the programming content in a fashion that is acceptable to the content providers. Lack of industry consensus on suitable DVR content protection mechanisms can hamper mass-market success of the digital set-top box. The approach should prevent, or significantly hinder, an individual or small group of interested people from reverse engineering the DVR design to gain an unsecured copy of the content. Additionally, the approach should prevent the distribution of a “solution” that allows a large number of people to gain a personal copy of the DVR content.
A number of content protection methodologies have emerged, particularly with respect to security techniques in the disk drives. Disk drive manufacturers offer a variety of security techniques, such as the use of hidden sectors, restricted sectors, and encryption. Under the hidden sectors approach, various sectors of the hard disk drive that contain DVR content would not be visible to a personal computer (PC) running standard software. A drawback with this approach is that it is not particularly secure. A sufficiently knowledgeable consumer could monitor the disk drive interface of the set-top box and reverse engineer the hidden sectors. This knowledgeable consumer could then write custom PC software to make the hidden sectors visible to the PC. Such custom software would make the disks with hidden sectors roughly equivalent to those with normal sectors. This custom software may then be widely disseminated; for example, through the Internet.
Another approach is to restrict access to the sectors of the hard disk that contains the programing content. This mechanism does not permit the restricted sectors to be accessed without a suitable password, even though the sectors are visible. However, such an arrangement has the same drawback as that of the hidden sector protection mechanism, in that a sufficiently knowledgeable person can monitor the disk drive interface and capture the password, and accordingly, write custom PC software to provide the password when needed.
Some disk drive manufactures offer data encryption as the data is written to the disk and decryption as it is retrieved. Several variations of this concept exist, depending on the particular manufacturer. Approaches that provide the decrypt key in the clear suffer from the same problem previously discussed. That is, a sufficiently knowledgeable person can monitor the disk drive interface and capture the decryption key. This could be enhanced with public/private key encryption, but would require tight coupling between the disk drive manufacturer and the set-top manufacturer (not to mention increased per unit cost of the set-top boxes). The security of this approach depends more on the two manufacturers' ability to generate and manage unique disk drive/set-top key pairs than on the strength of the encryption. The tight coupling between keys in the set-top and drive dramatically complicates warranty repairs and other field support issues. Furthermore, both the encryption and decryption processes introduce latency in the recording and replaying of the content.
Based on the foregoing, there is a clear need for improved approaches to providing a Digital Video Recording (DVR) content protection mechanism.
There is also a need to provide a simple protection mechanism
There is a further need to supply a cost effective solution.
Therefore, an approach for preventing unauthorized copying of digital data is highly desirable.